Do not use DOS epoch for timestamps of zip entries in Android rules

**Background**
I noticed cache output inconsistencies between my local and CI builds. I traced it down to the zip library in Java includes the timezone info within the extra field section of each zip entry. This appears to be a problem starting with Java 8 (See comment from Gradle's ZipCopyAction source code for more info: https://github.com/gradle/gradle/blob/master/subprojects/core/src/main/java/org/gradle/api/internal/file/archive/ZipCopyAction.java#L42-L56)

**Changes**
* Switch to using `February 1, 1980` instead to avoid this edge case

**Test Plan**
Ensure unit tests pass

Closes #10976.

PiperOrigin-RevId: 317075345

src/test/java/com/google/devtools/build/android/RClassGeneratorActionTest.java

diff --git a/src/test/java/com/google/devtools/build/android/RClassGeneratorActionTest.java b/src/test/java/com/google/devtools/build/android/RClassGeneratorActionTest.java
index 3dbf763..ca87e29 100644
--- a/src/test/java/com/google/devtools/build/android/RClassGeneratorActionTest.java
+++ b/src/test/java/com/google/devtools/build/android/RClassGeneratorActionTest.java
@@ -501,26 +501,23 @@
   }
 
   private static final class ZipMtimeAsserter {
-    private static final long ZIP_EPOCH = Instant.parse("1980-01-01T00:00:00Z").getEpochSecond();
-    private static final long ZIP_EPOCH_PLUS_ONE_DAY =
-        Instant.parse("1980-01-02T00:00:00Z").getEpochSecond();
+    private static final long DEFAULT_TIMESTAMP =
+        Instant.parse("1980-02-01T00:00:00Z").getEpochSecond();
+    private static final long DEFAULT_TIMESTAMP_PLUS_ONE_DAY =
+        Instant.parse("1980-02-02T00:00:00Z").getEpochSecond();
 
     public static void assertEntry(ZipEntry e) {
       // getLastModifiedTime().toMillis() returns milliseconds, Instant.getEpochSecond() returns
       // seconds.
       long mtime = e.getLastModifiedTime().toMillis() / 1000;
-      // The ZIP epoch is the same as the MS-DOS epoch, 1980-01-01T00:00:00Z.
-      // AndroidResourceOutputs.ZipBuilder sets this to most of its entries, except for .class files
-      // for which the ZipBuilder increments the timestamp by 2 seconds.
+      // AndroidResourceOutputs.ZipBuilder sets the timestamp to one month after ZIP epoch
+      // which is the same as the MS-DOS epoch, 1980-01-01T00:00:00Z.
+      // The one exception being .class files for which the ZipBuilder
+      // increments the timestamp by 2 seconds.
       // We don't care about the details of this logic and asserting exact timestamps would couple
       // the test to the code too tightly, so here we only assert that the timestamp is on
-      // 1980-01-01, ignoring the exact time.
-      // AndroidResourceOutputs.ZipBuilde sets the ZIP epoch (same as the MS-DOS epoch,
-      // 1980-01-01T00:00:00Z) as the timestamp for all of its entries (except .class files, for
-      // which it sets a timestamp 2 seconds later than the DOS epoch).
-      // We don't care about the exact timestamps though, only that they are stable, so let's just
-      // assert that they are all on the day of 1980-01-01.
-      if (mtime < ZIP_EPOCH || mtime > ZIP_EPOCH_PLUS_ONE_DAY) {
+      // 1980-02-01, ignoring the exact time.
+      if (mtime < DEFAULT_TIMESTAMP || mtime > DEFAULT_TIMESTAMP_PLUS_ONE_DAY) {
         Assert.fail(String.format("e=(%s) mtime=(%s)", e.getName(), e.getLastModifiedTime()));
       }
     }

src/tools/android/java/com/google/devtools/build/android/AndroidResourceOutputs.java

diff --git a/src/tools/android/java/com/google/devtools/build/android/AndroidResourceOutputs.java b/src/tools/android/java/com/google/devtools/build/android/AndroidResourceOutputs.java
index f6a82cb..575c82b 100644
--- a/src/tools/android/java/com/google/devtools/build/android/AndroidResourceOutputs.java
+++ b/src/tools/android/java/com/google/devtools/build/android/AndroidResourceOutputs.java
@@ -58,9 +58,13 @@
     // see http://www.info-zip.org/FAQ.html#limits
     private static final long MINIMUM_TIMESTAMP_INCREMENT = 2000L;
 
-    // The earliest date representable in a zip file, 1-1-1980 (the DOS epoch).
-    private static final long ZIP_EPOCH =
-        new GregorianCalendar(1980, Calendar.JANUARY, 01, 0, 0).getTimeInMillis();
+    /**
+     * Normalized timestamp for zip entries We use the system's default timezone and locale and
+     * additionally avoid using the DOS epoch to ensure Java's zip implementation does not add the
+     * System's timezone into the extra field of the zip entry
+     */
+    private static final long DEFAULT_TIMESTAMP =
+        new GregorianCalendar(1980, Calendar.FEBRUARY, 01, 0, 0).getTimeInMillis();
 
     private final ZipOutputStream zip;
 
@@ -84,9 +88,9 @@
      */
     protected long normalizeTime(String filename) {
       if (filename.endsWith(".class")) {
-        return ZIP_EPOCH + MINIMUM_TIMESTAMP_INCREMENT;
+        return DEFAULT_TIMESTAMP + MINIMUM_TIMESTAMP_INCREMENT;
       } else {
-        return ZIP_EPOCH;
+        return DEFAULT_TIMESTAMP;
       }
     }