Make lots of tests run in parallel

Putting t.Parallel() in each test makes them run in parallel.
Additional t.Parallel() could be added to each subtest, although
that requires making a local copy of the loop variable for
table driven tests.

Test: m checkbuild
Change-Id: I5d9869ead441093f4d7c5757f2447385333a95a4
diff --git a/android/onceper_test.go b/android/onceper_test.go
index 1a55ff4..da0b10d 100644
--- a/android/onceper_test.go
+++ b/android/onceper_test.go
@@ -20,6 +20,7 @@
 )
 
 func TestOncePer_Once(t *testing.T) {
+	t.Parallel()
 	once := OncePer{}
 	key := NewOnceKey("key")
 
@@ -36,6 +37,7 @@
 }
 
 func TestOncePer_Once_wait(t *testing.T) {
+	t.Parallel()
 	once := OncePer{}
 	key := NewOnceKey("key")
 
@@ -51,6 +53,7 @@
 }
 
 func TestOncePer_Get(t *testing.T) {
+	t.Parallel()
 	once := OncePer{}
 	key := NewOnceKey("key")
 
@@ -67,6 +70,7 @@
 }
 
 func TestOncePer_Get_panic(t *testing.T) {
+	t.Parallel()
 	once := OncePer{}
 	key := NewOnceKey("key")
 
@@ -82,6 +86,7 @@
 }
 
 func TestOncePer_Get_wait(t *testing.T) {
+	t.Parallel()
 	once := OncePer{}
 	key := NewOnceKey("key")
 
@@ -97,6 +102,7 @@
 }
 
 func TestOncePer_OnceStringSlice(t *testing.T) {
+	t.Parallel()
 	once := OncePer{}
 	key := NewOnceKey("key")
 
@@ -113,6 +119,7 @@
 }
 
 func TestOncePer_Once2StringSlice(t *testing.T) {
+	t.Parallel()
 	once := OncePer{}
 	key := NewOnceKey("key")
 
@@ -129,6 +136,7 @@
 }
 
 func TestNewOnceKey(t *testing.T) {
+	t.Parallel()
 	once := OncePer{}
 	key1 := NewOnceKey("key")
 	key2 := NewOnceKey("key")
@@ -146,6 +154,7 @@
 }
 
 func TestNewCustomOnceKey(t *testing.T) {
+	t.Parallel()
 	type key struct {
 		key string
 	}
@@ -166,6 +175,7 @@
 }
 
 func TestOncePerReentrant(t *testing.T) {
+	t.Parallel()
 	once := OncePer{}
 	key1 := NewOnceKey("key")
 	key2 := NewOnceKey("key")
@@ -178,6 +188,7 @@
 
 // Test that a recovered panic in a Once function doesn't deadlock
 func TestOncePerPanic(t *testing.T) {
+	t.Parallel()
 	once := OncePer{}
 	key := NewOnceKey("key")