Update the iOS project for Xcode 12.

- Move the min up to iOS 9.  Things should still work with 8, just can't have
  the project set to that and be able to run the tests, so moving it up to
  support running the tests.
- Remove the bitcode setting from the unittest bundle, was causing an error
  with Xcode 12.

objectivec/ProtocolBuffers_iOS.xcodeproj/project.pbxproj

@@ -856,13 +856,11 @@
 			buildSettings = {
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_WEAK = YES;
-				ENABLE_BITCODE = YES;
 				FRAMEWORK_SEARCH_PATHS = (
 					"\"$(DEVELOPER_LIBRARY_DIR)/Frameworks\"",
 					"$(inherited)",
 				);
 				INFOPLIST_FILE = "Tests/UnitTests-Info.plist";
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				LIBRARY_SEARCH_PATHS = (
 					"$(inherited)",
@@ -889,13 +887,11 @@
 			buildSettings = {
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_WEAK = YES;
-				ENABLE_BITCODE = YES;
 				FRAMEWORK_SEARCH_PATHS = (
 					"\"$(DEVELOPER_LIBRARY_DIR)/Frameworks\"",
 					"$(inherited)",
 				);
 				INFOPLIST_FILE = "Tests/UnitTests-Info.plist";
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				LIBRARY_SEARCH_PATHS = (
 					"$(inherited)",
@@ -972,7 +968,7 @@
 				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				GENERATE_PROFILING_CODE = NO;
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				ONLY_ACTIVE_ARCH = YES;
 				RUN_CLANG_STATIC_ANALYZER = YES;
 				SDKROOT = iphoneos;
@@ -1041,7 +1037,7 @@
 				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				GENERATE_PROFILING_CODE = NO;
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				RUN_CLANG_STATIC_ANALYZER = YES;
 				SDKROOT = iphoneos;
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";