Add missing 'arch' key to valid qHostInfo keys

Summary:
'arch' is a valid qHostInfo key, but the unit
test for qHostInfo did not include it in the set of possible keys.

Reviewers: tfiala, labath

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D32711

llvm-svn: 302260

lldb/packages/Python/lldbsuite/test/tools/lldb-server/TestGdbRemoteHostInfo.py

@@ -14,6 +14,7 @@ class TestGdbRemoteHostInfo(GdbRemoteTestCaseBase):
     mydir = TestBase.compute_mydir(__file__)
 
     KNOWN_HOST_INFO_KEYS = set([
+        "arch",
         "cputype",
         "cpusubtype",
         "distribution_id",