PNaCl: ExpandTls: Simplify by using a C++11 lambda function

Now that we can use C++11 lambdas, we can define addVarToTlsTemplate()
as a local function rather than using a class (PassState).

Since padToAlignment() only had one call site now, we can inline it
into addVarToTlsTemplate().

BUG=https://bugs.chromium.org/p/nativeclient/issues/detail?id=4351
TEST=test/Transforms/NaCl/expand-tls*.ll
R=smklein@chromium.org

Review URL: https://codereview.chromium.org/1780463004 .
1 file changed