Rename ApexName to ApexVariationName

In preparation for reusing the same variation for multiple apexes,
rename ApexName to ApexVariationName.

Bug: 164216768
Test: all soong tests
Change-Id: I88f2c5b192ffa27acd38e01952d0cefd413222a0
diff --git a/cc/binary.go b/cc/binary.go
index 63bbd83..6769fa7 100644
--- a/cc/binary.go
+++ b/cc/binary.go
@@ -445,7 +445,7 @@
 	// The original path becomes a symlink to the corresponding file in the
 	// runtime APEX.
 	translatedArch := ctx.Target().NativeBridge == android.NativeBridgeEnabled
-	if InstallToBootstrap(ctx.baseModuleName(), ctx.Config()) && !translatedArch && ctx.apexName() == "" && !ctx.inRamdisk() && !ctx.inRecovery() {
+	if InstallToBootstrap(ctx.baseModuleName(), ctx.Config()) && !translatedArch && ctx.apexVariationName() == "" && !ctx.inRamdisk() && !ctx.inRecovery() {
 		if ctx.Device() && isBionic(ctx.baseModuleName()) {
 			binary.installSymlinkToRuntimeApex(ctx, file)
 		}