Tests: add TEST_GLOBALS and TEST_GLOBALS_HTTP config chunks.

TEST_GLOBALS replaces previously used -g switch.  This allows tests
to be executed on 0.6.* branch.  For compatibility with old tests -g switch
will be used if TEST_GLOBALS wasn't expaneded in config.

TEST_GLOBALS_HTTP replaces multiple variables (access_log, root,
client_body_temp_path, proxy_temp_path, fastcgi_temp_path) previously
specified directly in test configs.  This change reduce duplication and
allows tests to be used with nginx compiled without fastcgi and/or proxy
modules (as proxy_temp_path and fastcgi_temp_path are added conditionally).
diff --git a/range-flv.t b/range-flv.t
index 00507b0..0653a16 100644
--- a/range-flv.t
+++ b/range-flv.t
@@ -25,6 +25,8 @@
 
 $t->write_file_expand('nginx.conf', <<'EOF');
 
+%%TEST_GLOBALS%%
+
 master_process off;
 daemon         off;
 
@@ -32,12 +34,7 @@
 }
 
 http {
-    access_log    off;
-    root          %%TESTDIR%%;
-
-    client_body_temp_path  %%TESTDIR%%/client_body_temp;
-    fastcgi_temp_path      %%TESTDIR%%/fastcgi_temp;
-    proxy_temp_path        %%TESTDIR%%/proxy_temp;
+    %%TEST_GLOBALS_HTTP%%
 
     server {
         listen       127.0.0.1:8080;