Thread Safety Analysis: fix broken test.

[jmgao]

Summary

rL309725 switched assert_capability/assert_shared_capability to support
multiple locks to match assert_exclusive_lock/assert_shared_lock, but
the corresponding test that a warning is emitted when multiple locks
are passed wasn't removed. Remove it.

test/Sema/attr-capabilities.c

 void Func4(void) __attribute__((requires_shared_capability)) {}  // expected-error {{'requires_shared_capability' attribute takes at least 1 argument}}
 
 void Func5(void) __attribute__((requires_capability(1))) {}  // expected-warning {{'requires_capability' attribute requires arguments whose type is annotated with 'capability' attribute; type here is 'int'}}
 void Func6(void) __attribute__((requires_shared_capability(BadCapability))) {}  // expected-warning {{'requires_shared_capability' attribute requires arguments whose type is annotated with 'capability' attribute; type here is 'struct NotACapability'}}
 
 void Func7(void) __attribute__((assert_capability(GUI))) {}
 void Func8(void) __attribute__((assert_shared_capability(GUI))) {}
 
-void Func9(void) __attribute__((assert_capability())) {} // expected-error {{'assert_capability' attribute takes one argument}}
-void Func10(void) __attribute__((assert_shared_capability())) {} // expected-error {{'assert_shared_capability' attribute takes one argument}}
-
 void Func11(void) __attribute__((acquire_capability(GUI))) {}
 void Func12(void) __attribute__((acquire_shared_capability(GUI))) {}
 
 void Func15(void) __attribute__((release_capability(GUI))) {}
 void Func16(void) __attribute__((release_shared_capability(GUI))) {}
 void Func17(void) __attribute__((release_generic_capability(GUI))) {}
 
 void Func21(void) __attribute__((try_acquire_capability(1))) {}