Parser: allow multiple statements on the same line as the colon

 e.g. def foo(x, y): print(x); print(y)

Bug found when adding the pass statement.

--
MOS_MIGRATED_REVID=88852710

src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java

diff --git a/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java b/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java
index 51da72c..b6741c4 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java
@@ -756,6 +756,14 @@
   }
 
   @Test
+  public void testDefSingleLine() throws Exception {
+    List<Statement> statements = parseFileForSkylark(
+        "def foo(): x = 1; y = 2\n");
+    FunctionDefStatement stmt = (FunctionDefStatement) statements.get(0);
+    assertThat(stmt.getStatements()).hasSize(2);
+  }
+
+  @Test
   public void testSkipIfBlock() throws Exception {
     // Skip over 'if' blocks, when parsePython is set
     List<Statement> stmts = parseFile(