tools: Removed outdated (and broken) toolchain initialization test

Also moved the access of build_dir into condition on secure in ARMC6

per theotherjimmy

tools/test/toolchains/api_test.py

@@ -15,13 +15,6 @@ from tools.toolchains import TOOLCHAIN_CLASSES, LEGACY_TOOLCHAIN_NAMES,\
     Resources, TOOLCHAIN_PATHS, mbedToolchain
 from tools.targets import TARGET_MAP
 
-def test_instantiation():
-    """Test that all exported toolchain may be instantiated"""
-    for name, tc_class in  TOOLCHAIN_CLASSES.items():
-        cls = tc_class(TARGET_MAP["K64F"])
-        assert name == cls.name or\
-            name == LEGACY_TOOLCHAIN_NAMES[cls.name]
-
 ALPHABET = [char for char in printable if char not in [u'.', u'/']]
 
 @given(fixed_dictionaries({

tools/toolchains/arm.py

@@ -309,7 +309,6 @@ class ARMC6(ARM_STD):
             raise NotSupportedException(
                 "this compiler does not support the core %s" % target.core)
 
-        build_dir = kwargs['build_dir']
         if not set(("ARM", "ARMC6")).intersection(set(target.supported_toolchains)):
             raise NotSupportedException("ARM/ARMC6 compiler support is required for ARMC6 build")
 
@@ -349,6 +348,7 @@ class ARMC6(ARM_STD):
 
         # Create Secure library
         if target.core == "Cortex-M23" or self.target.core == "Cortex-M33":
+            build_dir = kwargs['build_dir']
             secure_file = join(build_dir, "cmse_lib.o")
             self.flags["ld"] += ["--import_cmse_lib_out=%s" % secure_file]