The expression BE to VERB has slightly different meanings in indicative and hypothetical contexts.
In indicative contexts it means BE expected to VERB or BE scheduled to VERB in the future
I am to see the doctor on Wednesday. = I have an appointment with the doctor for Wednesday.
He was to become the next CEO, but retired before that could happen. = It was planned that he would become the next CEO, but ...
In hypothetical contexts, where we employ the past form of a verb uninflected for person† to indicate contingency or unreality, BE to VERB loses the sense of expectation or scheduling; it is simply an alternative to the bare past form of VERB. It is slightly more formal than that bare past form, and slightly more strongly marked for hypotheticality—probably because it is a longer form than the bare past. But these two sentences are semantically equivalent:
If I were to say what I think I would be fired.
If I said what I think I would be fired.
Your examples are tricky. Strictly speaking, from a 'western English' perspective, they are ungrammatical: in both sentences, the PM combines hypothetical forms were to become/come in the IF clauses with indicative forms do not intend/will prove to be in the THEN clauses.
I take it that in the first sentence, at least, where the PM is quoted directly, this awkwardness arises because he is speaking off-the-cuff and improvising the proper expression of a firm intention or prediction concerning an event, the future elections, whose outcome is entirely hypothetical. In the second the mistake may be the PM's or it may be that of the journalist who is paraphrasing him.
But I cannot rule out the possibility that Indian English—and specifically Indian Political English—has evolved this usage of were to precisely in order to express firmness and caution in the same utterance. Perhaps our Indian readers could speak to this.
† This use is called subjunctive in traditional grammar.