Apply suggestions from code review

Author: vchuravy

src/cache.jl

@@ -62,7 +62,7 @@ const specialization_counter = Ref{UInt}(0)
     return new_ci
 end
 
-const disk_cache = parse(Bool, @load_preference("disk_cache", "false"))
+const disk_cache = @load_preference("disk_cache", false)
 const cache_key = @load_preference("cache_key", "")
 
 """
@@ -85,7 +85,7 @@ end
 
 If you are deploying an application it is recommended that you use your
 application name and version as a cache key. To minimize the risk of
-encountering spurios cache hits.
+encountering spurious cache hits.
 """
 function set_cache_key(key)
     @set_preferences!("cache_key"=>key)

test/CacheEnv/LocalPreferences.toml

@@ -1,3 +1,3 @@
 [GPUCompiler]
-disk_cache = "true"
-cache_key = "test"
+disk_cache = true
+cache_key = "test"

test/runtests.jl

@@ -36,7 +36,7 @@ haskey(ENV, "CI") && GPUCompiler.timings()
         cmd = `$cmd --project=$(unsafe_string(Base.JLOptions().project))`
     end
 
-    withenv("JULIA_LOAD_PATH" => "$(get(ENV, "JULIA_LOAD_PATH", "")):$(joinpath(@__DIR__, "CacheEnv"))" do
+    withenv("JULIA_LOAD_PATH" => "$(get(ENV, "JULIA_LOAD_PATH", "")):$(joinpath(@__DIR__, "CacheEnv"))") do
         @test success(pipeline(`$cmd cache.jl true`, stderr=stderr, stdout=stdout))
         @test success(pipeline(`$cmd cache.jl false`, stderr=stderr, stdout=stdout))
     end